合并具有不同列数的表

Question

I need to UNION two tables that have mostly the same columns, but one has several additional columns. I'm aware that you can do a SELECT with placeholders for those additional columns, but I'm working with about 200 columns, and the bigger table has about 30 additional columns. This makes it unreasonable to type out every column. Is there a way to union the tables while automatically setting a NULL value for the columns that don't exist in the smaller table?

Answer 1

In short, no. Unioning result sets together must have the same number / data type of columns. If you wanted to have the remaining sets populate null, the simplest way to do this would be to do something like so-

select col1
, col2
, col3
, col4
from tbl1

union all

select null as col1
, null as col2
, null as col3
, null as col4
from tbl2